Simple circuit connects to the sub-woofer output and modulates a neon light to the beat of the bass

By Rick Walters

Our last neon tube modulator for cars (SILICON CHIP May 1997) proved quite popular, but what do you do if you don’t have
a sub-woofer output from your stereo system to drive it? This latest version
solves that problem.

As well, the original unit turned off the neon tube for each
bass beat but some readers wanted the neon to fire on the beat. This unit can do
both.

Oh! You do have a sub output on your system but you’d
like to use this updated circuit? No worries, just omit three capacitors and off
you go.

How it works

Fig.1: the complete circuit has just one IC, three transistors, a couple of diodes and a small handful of resistors and capacitors. LED1 is not shown on this circuit: see the wiring diagram.

As you can see from the circuit (Fig.1) and photograph of the
PC board there isn’t a lot to it. One IC, three transistors, a couple of diodes
and a small handful of resistors and capacitors and its done.